Immobilized photocatalyst on stainless steel woven meshes assuring efficient light distribution in a solar reactor

Abstract

Abstract. An immobilized TiO2 photocatalyst with a high specific surface area was prepared on stainless steel woven meshes in order to be used packed in layers for water purification. Immobilization of such a complex shape needs a special coating technique. For this purpose, dip coating and electrophoretic deposition (EPD) techniques were used. The EPD technique gave the TiO2 coating films a better homogeneity and adhesion, fewer cracks, and a higher ·OH formation than the dip coating technique. The woven mesh structure packed in layers guaranteed an efficient light-penetration in water treatment reactor. A simple equation model was used to describe the distribution of light through the mesh layers in the presence of absorbing medium (e.g., colored water with humic acids). Maximum three or four coated meshes were enough to harvest the solar UV light from 300 nm to 400 nm with a high penetration efficiency. The separation distance between the mesh layers played an important role in the efficiency of solar light penetration through the coated mesh layers, especially in case of colored water contaminated with high concentrations of humic acid.

Solar-Driven Photocatalytic Films: Synthesis Approaches, Factors Affecting Environmental Activity, and Characterization Features

“…Techniques used for measuring adhesion are applied sparingly in the research community, but the most common are the Wolff–Wilborn test (ISO 15184) [ 157 ], ultrasonication [ 158 , 159 ], the Scotch tape test [ 160 ], and the cross-hatch adhesion test according to ASTM D 3359B-02 [ 161 , 162 ]. The latter seems convenient since the peel strength of 3M 600 tape is 0.44 N mm −1 .…”

Photocatalytic degradation of atrazine by an N-doped TiO2/polymer composite: catalytic efficiency and toxicity evaluation

“…Although sPS/NdT composite is always more active in the ATZ degradation than NdT powder, the degradation kinetics, faster for UV than Vis irradiation, were however very similar to each other. This result is very interesting since it is well known that, when a photocatalyst is immobilized in granular form or as thin film on macroscopic supports, the screening of the light by the support itself occurs and, moreover, the accessibility of the catalytic surface to the photons and to the reactants worsens, J o u r n a l P r e -p r o o f inducing a photocatalytic activity significantly lower than that achieved when the photocatalysts are used in powder form [75][76][77].…”

Combination of immobilized TiO2 and zero valent iron for efficient arsenic removal in aqueous solutions

“…Such shortcomings can be overcome by using reactors with immobilized TiO 2 so that no separation of the catalyst particles is needed, also improving the reutilization of the catalyst in consecutive cycles. Nevertheless, compared to slurry operation mode, immobilized systems show a lower accessibility of the catalyst to photons, and a low area-to-volume ratio which can lead to mass transfer limitations and low reaction rates (Balasubramanian et al, 2004;El-Kalliny et al, 2014;Singh et al, 2013;Chen et al, 2001). Accordingly, the rate of the reaction and the pollutant transformation achieved will be significantly affected by the thickness of the layer of immobilized catalyst, since it governs the extent of radiation that can be absorbed and also the limitations of access to the photocatalyst close to the support due to the internal mass transfer (Vezzoli et al, 2013).…”